Feature: 1. Maximum/minimum value measurement and data retention function, can measure the volume more easily. 2. Data recording function, data measurement and collection are more convenient. 3. Real‑time display of results, with fast/slow response modes to choose from. 4. Scientific design, the test process is more accurate, and the test data is more rigorous. 5. The product is small in size, light in weight, easy to transport and convenient to use Specification: Item Type: Noise Tester Material: Plastic Size: Approx. 23x7cm / 9.1x2.8in Weight: Approx. 618g / 21.8oz Sensor: 1/2 Inch Condenser Microphone Measuring Range: 30~130dBA/35~130dBC Measurement Accuracy: ±1.5dB Frequency Response: 31.5Hz~8.5KHz Frequency Weighting: A/C Digits: 5 Digits Resolution: 01dB Time Weighting: Fast/Slow Maximum Lock: Support Power Supply: 4x1.5V AA Batteries (Batteries Not Included). Package List: 1 x Noise Tester (Battery Not Included)1 x Manual1 x Power Cord1 x Circle Protector Note: 1. Do not place it in a high temperature or humid place.2. The ambient noise must be lower than the noise of the measured object before it can be measured normally.3. Please take out the battery if you don't use it for a long time to avoid electrolyte leakage and damage the meter.